U.S. patent application number 14/029288 was filed with the patent office on 2014-11-20 for method and apparatus for enabling efficient resource allocation.
This patent application is currently assigned to Telefonaktiebolaget L M Ericsson (PUBL). The applicant listed for this patent is Telefonaktiebolaget L M Ericsson (PUBL). Invention is credited to Sriganesh Kini.
Application Number | 20140341016 14/029288 |
Document ID | / |
Family ID | 51895688 |
Filed Date | 2014-11-20 |
United States Patent
Application |
20140341016 |
Kind Code |
A1 |
Kini; Sriganesh |
November 20, 2014 |
METHOD AND APPARATUS FOR ENABLING EFFICIENT RESOURCE ALLOCATION
Abstract
Embodiments of the present disclosure include a method and
intermediate label switch router (LSR) for enabling efficient
resource allocation for point to multi-point signaling. In one
embodiment, upstream traffic specification information associated
with a plurality of spoke nodes is received. The upstream traffic
specification information is sent to a hub. Upstream flow
specification information is received from the hub. The upstream
flow specification information is used to allocate resources among
the plurality of spoke nodes proportionally or in accordance with a
resource sharing mode. A method and hub for enabling efficient
resource allocation for point to multi-point signaling is also
disclosed. In one embodiment, upstream traffic specification
information is received from an intermediate label switch router.
The upstream traffic specification information can be an upstream
traffic specification list. The upstream traffic specification list
is used to generate an upstream flow specification for each
respective sub label switch path (sub-LSP).
Inventors: |
Kini; Sriganesh; (Fremont,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget L M Ericsson (PUBL) |
Stockholm |
|
SE |
|
|
Assignee: |
Telefonaktiebolaget L M Ericsson
(PUBL)
Stockholm
SE
|
Family ID: |
51895688 |
Appl. No.: |
14/029288 |
Filed: |
September 17, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61823144 |
May 14, 2013 |
|
|
|
Current U.S.
Class: |
370/230 |
Current CPC
Class: |
H04L 47/76 20130101;
H04L 45/507 20130101; H04L 45/38 20130101; H04L 45/50 20130101 |
Class at
Publication: |
370/230 |
International
Class: |
H04L 12/917 20060101
H04L012/917 |
Claims
1. A method for enabling efficient resource allocation for point to
multi-point signaling using an intermediate label switched router
(LSR), which comprises: receiving upstream traffic specification
information associated with a plurality of spoke nodes; sending the
upstream traffic specification information to a hub; receiving
upstream flow specification information from the hub; and using the
upstream flow specification information to allocate resources among
the plurality of spoke nodes proportionally or in accordance with a
resource sharing mode.
2. The method of claim 1, wherein the upstream traffic
specification information is combined from the plurality of spoke
nodes.
3. The method of claim 2, wherein combining upstream traffic
specification information comprises determining a sum of upstream
traffic specifications from the plurality of spoke nodes.
4. The method of claim 2, wherein the upstream flow specification
information is received in a path message from the hub.
5. The method of claim 4, wherein the intermediate LSR generates an
upstream flow specification using a proportional flow specification
operation.
6. The method of claim 5, wherein the generated upstream flow
specification is calculated as a fraction of the received upstream
flow specification.
7. The method of claim 1, wherein the traffic specification
information for each spoke node is propagated to the hub.
8. The method of claim 7, wherein the traffic specification
information for each node is propagated to the hub using an
upstream traffic specification list generated by the intermediate
LSR.
9. The method of claim 8, wherein the upstream traffic
specification list is sent to the hub using an upstream sender
template.
10. A method for enabling efficient resource allocation for point
to multi-point signaling using a hub, which comprises: receiving
upstream traffic specification information from an intermediate
label switch router, the upstream traffic specification information
comprising an upstream traffic specification list; and using the
upstream traffic specification list to generate an upstream flow
specification for each respective sub label switch path
(sub-LSP).
11. The method of claim 10, wherein a format of the sub-LSP is
modified by appending a sub-LSP flow specification.
12. An intermediate label switched router (LSR) for enabling
efficient resource allocation for point to multi-point signaling,
comprising: a processor configured to: receive upstream traffic
specification information associated with a plurality of spoke
nodes; send the upstream traffic specification information to a
hub; receive upstream flow specification information from the hub;
and use the upstream flow specification information to allocate
resources among the plurality of spoke nodes proportionally or in
accordance with a resource sharing mode.
13. The intermediate LSR of claim 12, wherein the upstream traffic
specification information is combined from the plurality of spoke
nodes.
14. The intermediate LSR of claim 13, wherein combining upstream
traffic specification information comprises determining a sum of
upstream traffic specifications from the plurality of spoke
nodes.
15. The intermediate LSR of claim 13, wherein the upstream flow
specification information is received in a path message from the
hub.
16. The intermediate LSR of claim 15, wherein the intermediate LSR
generates an upstream flow specification using a proportional flow
specification operation.
17. The intermediate LSR of claim 12, wherein the traffic
specification information for each spoke node is propagated to the
hub.
18. The intermediate LSR of claim 17, wherein the traffic
specification information for each node is propagated to the hub
using an upstream traffic specification list generated by the
intermediate LSR.
19. The intermediate LSR of claim 18, wherein the upstream traffic
specification list is sent to the hub using an upstream sender
template.
20. A hub for enabling efficient resource allocation for point to
multi-point signaling, comprising: a processor configured to:
receive upstream traffic specification information from an
intermediate label switch router, the upstream traffic
specification information comprising an upstream traffic
specification list; and use the upstream traffic specification list
to generate an upstream flow specification for each respective sub
label switch path (sub-LSP).
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 61/823,144, filed on May 14, 2013, the entire
disclosure of which is hereby incorporated herein by reference in
its entirety.
FIELD
[0002] The present disclosure relates to point-to-multi-point
(P2MP) bi-directional label switched path (LSP), e.g., Hub and
Spoke Multipoint LSP (HSMP LSP) signaling. More particularly, the
present disclosure relates to protocol extensions for P2MP that
enable highly efficient resource allocation.
BACKGROUND
[0003] There are applications that require bi-directional,
co-routed and guaranteed communication from a root node to several
leaf nodes in a hub and spoke fashion. To meet such application
requirements in a Multi-protocol Label Switching (MPLS) network a
Hub and Spoke Multipoint Traffic Engineered Label Switched Path
(HSMP TE LSP) with resource reservations for guaranteed
communication has been defined. A protocol to setup such LSPs by
re-using and extending P2MP reservation protocol traffic
engineering (RSVP-TE) has also been defined.
[0004] There are many applications that require one-to-many
bi-directional communication. Making such applications work over a
MPLS network by using both P2MP and point-to-point (P2P) constructs
results in scalability issues. A technique has been defined to do
one-to-many bidirectional communication over an MPLS network that
re-uses the existing P2MP and P2P constructs in MPLS but combines
them in a scalable manner. This technique re-uses and extends the
current traffic-engineered P2MP and P2P constructs and
protocols.
[0005] Two representative applications are described that require
one-to-many bi-directional communication. The first is a `Time
Synchronization` application. The second is a P2MP pseudowire (PW)
application.
[0006] With time Synchronization, i.e., over an MPLS network, a
scalable time-sync architecture requires the master to provide time
synchronization to a large number of slaves. It requires the P2P
messages to flow bi-directionally between master and slave in a hub
and spoke manner. More importantly these messages must have the
same delay in both directions. This requires the underlying network
to reserve resources to transport P2P messages and also to co-route
them in both directions to avoid any differences in the delays of
the paths in both directions.
[0007] A P2MP PW is required for the virtual private multicast
service (VPMS) service. In this application the root provider edge
(PE) router requires bi-directional communication with several leaf
PEs. The underlying MPLS transport should support this type of
communication for the P2MP PW in a reliable and efficient
manner.
[0008] A straightforward method to achieve one-to-many
bi-directional communication with resource guarantees is to use a
P2MP RSVP-TE tunnel from the hub PE to the spoke PEs and use P2P
RSVP-TE tunnels from each spoke PE to the hub PE. The spoke-to-hub
P2P tunnels can be explicitly routed such that they are co-routed
along the reverse direction of the P2MP tunnel. In this model,
scalability issues arise both in the data plane and the control
plane.
[0009] An application with a hub and spoke bi-directional
communication over a tree topology MPLS network is illustrated in
FIG. 1. The hub label switch router (LSR) is A and the spoke LSRs
are E, F, G, and H. For communication from the hub to the spokes, a
P2MP LSP can be setup with A as the root and E, F, G and H as
leaves. For communication from the spokes to the hub, a P2P LSP can
be setup from each spoke to the hub.
[0010] Each LSR along this tree will have to allocate a unique
label for each of the P2P LSPs that go from spoke to hub through
it. This leads to a linear increase in forwarding state at each LSR
in proportion to the number of spoke nodes that are in its
sub-tree. This has poor scaling characteristics in the data plane
as the number of spoke nodes increase.
[0011] Each LSR also has to allocate a control plane state for each
of the P2P LSPs that go from spoke to hub through the respective
LSR. Each P2P LSP will need a separate path state block (PSB) and a
reservation state block (RSB) and these will store additional
information on signaling attributes. This state is in addition to
the state maintained for the P2MP LSP. Clearly this state increases
linearly with the number of spoke nodes that are in its sub-tree.
This approach exhibits poor scaling characteristics in the control
plane as the number of spoke nodes increase. Also the number of
signaling messages increases linearly though some of it may be
mitigated by using refresh reduction.
[0012] A hub and spoke traffic-engineered multipoint LSP (HSMP TE
LSP) is defined to solve the above issues with resource
reservations. Such an LSP is a combination of an explicitly routed
uni-directional traffic-engineered P2MP LSP from the hub to the
spokes and a co-routed uni-directional MP2P LSP from the spokes to
the hub. HSMP TE LSP operates on a data plane and a control
plane.
[0013] In the direction from hub-to-spoke the data plane processing
is the same as that of a P2MP LSP. In the direction from the spokes
to the hub, each LSR allocates labels for its upstream LSRs. Each
LSR merges the traffic received from multiple upstream LSRs before
forwarding it on the LSP towards the hub. It should be noted that
due to label merging the generic alert label (GAL) processing in
the direction from spoke to hub is not defined.
[0014] The signaling protocol to setup a HSMP TE LSP can re-use the
signaling protocol for P2MP RSVP-TE (RFC4875) with some extensions.
The hub and spokes of a HSMP LSP can be modeled the same as the
source and leaves, respectively, of a P2MP LSP. A source-to-leaf
(S2L) sub-LSP defined in RFC4875 for the P2MP LSP is used to
represent a hub-to-spoke communication of the HSMP LSP. The
bidirectional co-routed nature of the communication from the hub to
the spoke must be signaled using the extensions defined in section
3 of RFC3473. Each Path message of a HSMP LSP LSR must have a
Upstream_Label object. If a PathErr is received in response with a
"Routing problem/Unacceptable label value" indication then the
Acceptable Label Set (if present) must be examined to allocate a
label for the Upstream_Label object. If an LSR signaling an HSMP
LSP receives PathErr messages with different Acceptable Label Sets
from different neighboring LSRs then the LSR may need to allocate
more than one label to satisfy all the Acceptable Label Sets. The
LSR should try to minimize the number of unique labels allocated
for a HSMP LSP in such a case.
[0015] Pruning and grafting for a HSMP LSP follow the same
procedures as for a P2MP LSP. During re-merge in addition to the
procedures in section 18.1.1 of RFC4875, the ingress or transit LSR
that creates the branch would also be a re-merge LSR for the
traffic from the spokes towards the hub. Also the re-merge node for
the traffic from hub to spoke would be a branching node for traffic
from the spokes to the hub. The LSR that is branching the traffic
from the spokes to the hub would duplicate the traffic whereas the
LSR that is re-merging the traffic should forward traffic only from
one the incoming interfaces.
[0016] The HSMP LSP also requires bandwidth allocation that is
asymmetric between the hub-to-spoke and the spoke-to-hub direction.
At the same time it requires the spokes to be able to request
different amounts of bandwidth towards the hub. The protocol
extensions defined in RFC6387 are used for asymmetric bandwidth
allocation between the hub-to-spoke and spoke-to-hub directions.
Upstream traffic specification (UPSTREAM_TSPEC), upstream
advertisement specification (UPSTREAM_ADSPEC) and upstream flow
specification (UPSTREAM_FLOWSPEC) objects are also used in a HSMP
LSP. An adspec is an object in a path message that carries a
package of one pass with advertising (OPWA) information. However in
case of a HSMP LSP an intermediate LSR can receive different
UPSTREAM_TSPECs in the reservation request (Resv) messages from
neighboring LSRs.
[0017] Some applications require a hub and spoke style
bi-directional communication with resource reservation. Example
applications are time synchronization and P2MP pseudowire. The
spoke to hub direction of communication is a multipoint-to-point
communication pattern and existing protocols such as RSVP-TE
(RFC3209) or P2MP RSVP-TE (RFC4875) do not support resource
reservation for such cases. One method to support resource
reservation is combining the RFC4875 procedures with RFC6387.
However the limitations of the RFC4875 specifications lead to a
highly inefficient resource reservation. Combining RFC4875 and
RFC6387 so that the bandwidth is efficiently allocated is not
defined in the current standard specifications.
[0018] Therefore, there is a need in the art to solve the above
described problems and perform resource reservations in a highly
efficient yet scalable manner for the spoke to hub direction of a
hub and spoke multipoint LSP.
SUMMARY
[0019] Disclosed is a method and intermediate label switch router
(LSR) for enabling efficient resource allocation for point to
multi-point signaling. In one embodiment, upstream traffic
specification information associated with a plurality of spoke
nodes is received. The upstream traffic specification information
is sent to a hub. Upstream flow specification information is
received from the hub. The upstream flow specification information
is used to allocate resources among the plurality of spoke nodes
proportionally or in accordance with a resource sharing mode.
[0020] The upstream traffic specification information is combined
from the plurality of spoke nodes. Combining upstream traffic
specification information can be accomplished by determining a sum
of upstream traffic specifications from the plurality of spoke
nodes.
[0021] In one embodiment, the upstream flow specification
information is received in a path message from the hub. The
intermediate LSR can generate an upstream flow specification using
a proportional flow specification operation. The generated upstream
flow specification can be calculated as a fraction of the received
upstream flow specification.
[0022] In one embodiment, the traffic specification information for
each spoke node is propagated to the hub. The traffic specification
information for each node can be propagated to the hub using an
upstream traffic specification list generated by the intermediate
LSR. The upstream traffic specification list can be sent to the hub
using an upstream sender template.
[0023] A method and hub for enabling efficient resource allocation
for point to multi-point signaling is disclosed. In one embodiment,
upstream traffic specification information is received from an
intermediate label switch router. The upstream traffic
specification information can be an upstream traffic specification
list. The upstream traffic specification list is used to generate
an upstream flow specification for each respective sub label switch
path (sub-LSP). In one embodiment, a format of the sub-LSP is
modified by appending a sub-LSP flow specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The present invention is illustrated by way of example, and
not by way of limitation, in the figures of the accompanying
drawings in which like references indicate similar elements. It
should be noted that different references to "an" or "one"
embodiment in this disclosure are not necessarily to the same
embodiment, and such references mean at least one. Further, when a
particular feature, structure, or characteristic is described in
connection with an embodiment, it is submitted that it is within
the knowledge of one skilled in the art to affect such feature,
structure, or characteristic in connection with other embodiments
whether or not explicitly described.
[0025] FIG. 1 is an illustration of tree topology for a
multi-protocol label switching network.
[0026] FIG. 2 is an illustration of a hub and spoke system
according to one embodiment.
[0027] FIG. 3 is an illustration of a system diagram of a message
flow according to one embodiment.
[0028] FIG. 4 is an illustration of a system diagram of a message
flow according to one embodiment.
[0029] FIG. 5 is a block diagram of a method for enabling efficient
resource allocation for point to multi-point signaling using an
intermediate label switch router according to one embodiment.
[0030] FIG. 6 is a block diagram of a method for enabling efficient
resource allocation for point to multi-point signaling using a hub
according to one embodiment.
[0031] FIG. 7 is an illustration of an example network node or
element according to one embodiment.
DESCRIPTION OF EMBODIMENTS
[0032] In the following description, numerous specific details are
set forth. However, it is understood that embodiments of the
invention may be practiced without these specific details. In other
instances, well-known circuits, structures and techniques have not
been shown in detail in order not to obscure the understanding of
this description. It will be appreciated, however, by one skilled
in the art that the invention may be practiced without such
specific details. Those of ordinary skill in the art, with the
included descriptions, will be able to implement appropriate
functionality without undue experimentation.
[0033] References in the specification to "one embodiment", "an
embodiment", "an example embodiment", etc., indicate that the
embodiment described may include a particular feature, structure,
or characteristic, but every embodiment may not necessarily include
the particular feature, structure, or characteristic. Moreover,
such phrases are not necessarily referring to the same embodiment.
Further, when a particular feature, structure, or characteristic is
described in connection with an embodiment, it is submitted that it
is within the knowledge of one skilled in the art to effect such
feature, structure, or characteristic in connection with other
embodiments whether or not explicitly described.
[0034] In the following description and claims, the terms "coupled"
and "connected," along with their derivatives, may be used. It
should be understood that these terms are not intended as synonyms
for each other. "Coupled" is used to indicate that two or more
elements, which may or may not be in direct physical or electrical
contact with each other, co-operate or interact with each other.
"Connected" is used to indicate the establishment of communication
between two or more elements that are coupled with each other.
[0035] As used herein, a network element (e.g., a router, switch,
bridge) is a piece of networking equipment, including hardware and
software that communicatively interconnects other equipment on the
network (e.g., other network elements, end stations). Some network
elements are "multiple services network elements" that provide
support for multiple networking functions (e.g., routing, bridging,
switching, Layer 2 aggregation, session border control, Quality of
Service, and/or subscriber management), and/or provide support for
multiple application services (e.g., data, voice, and video).
Subscriber end stations (e.g., servers, workstations, laptops,
netbooks, palm tops, mobile phones, smartphones, multimedia phones,
Voice Over Internet Protocol (VOIP) phones, user equipment,
terminals, portable media players, tablets, GPS units, gaming
systems, set-top boxes) access content/services provided over the
Internet and/or content/services provided on virtual private
networks (VPNs) overlaid on (e.g., tunneled through) the Internet.
The content and/or services are typically provided by one or more
end stations (e.g., server end stations) belonging to a service or
content provider or end stations participating in a peer to peer
service, and may include, for example, public webpages (e.g., free
content, store fronts, search services), private webpages (e.g.,
username/password accessed webpages providing email services),
and/or corporate networks over VPNs. Typically, subscriber end
stations are coupled (e.g., through customer premise equipment
coupled to an access network (wired or wirelessly)) to edge network
elements, which are coupled (e.g., through one or more core network
elements) to other edge network elements, which are coupled to
other end stations (e.g., server end stations).
[0036] Different embodiments of the invention may be implemented
using different combinations of software, firmware, and/or
hardware. Thus, the techniques shown in the figures can be
implemented using code and data stored and executed on one or more
electronic devices (e.g., an end station, a network element). Such
electronic devices store and communicate (internally and/or with
other electronic devices over a network) code and data using
computer-readable media, such as non-transitory computer-readable
storage media (e.g., magnetic disks; optical disks; random access
memory; read only memory; flash memory devices; phase-change
memory) and transitory computer-readable transmission media (e.g.,
electrical, optical, acoustical or other form of propagated
signals--such as carrier waves, infrared signals, digital signals).
In addition, such electronic devices typically include a set of one
or more processors coupled to one or more other components, such as
one or more storage devices (non-transitory machine-readable
storage media), user input/output devices (e.g., a keyboard, a
touchscreen, and/or a display), and network connections. The
coupling of the set of processors and other components is typically
through one or more busses and bridges (also termed as bus
controllers). Thus, the storage device of a given electronic device
typically stores code and/or data for execution on the set of one
or more processors of that electronic device.
[0037] Presently disclosed are procedures including protocol
extensions for the signaling protocol (P2MP RSVP-TE) that enable a
highly efficient resource allocation. Disclosed are two approaches
or methods for achieving this highly efficient resource
allocation.
[0038] The proportional method (P-method) makes no change to the
signaling protocol packet format. As such, the P-method is more
backward compatible. The downside is that this method does not give
the hub LSR fine-grained control over the resource allocations to
each spoke LSR.
[0039] The granular method (G-method) allows the hub LSR
fine-grained control over the resource allocation to each spoke
LSR. In order to implement the G-method, protocol changes are
needed. Hence, this method is not as backward compatible as the
P-method.
[0040] FIG. 2 illustrates a hub and spoke system. Hub, H, is
coupled to intermediate node, A, which is coupled to upstream node,
B, and spoke, S. Upstream node, B, is also coupled to spokes, S1,
S2, . . . , Sn-1. Spokes (S1, S2, . . . , Sn-1, S) can also be
referred to as spoke nodes or leaf nodes 310. Efficient resource
allocation is accomplished by factoring in traffic specifications
received from each directly coupled node 305, e.g., the plurality
of traffic specifications received from upstream node B and the
traffic specification received from spoke S.
[0041] The reservation style defined in RFC2205 applies to two
different LSPs of the same LSP tunnel. In one embodiment, the
present disclosure defines a reservation style between different
S2L sub LSPs of a HSMP LSP. This reservation style applies to the
reservation for the traffic direction from spoke to hub (in other
words from leaf to source). This reservation style is henceforth
referred to as L2S Style.
[0042] The L2S Style is signaled in P2MP RSVP-TE using encoding
similar to the STYLE object defined in section A.7 of RFC2205 and
is denoted as the L2S_STYLE object. Section A.7 discloses the
following style class: STYLE class=8. In accordance with the
present disclosure, a new class number is allocated to identify the
L2S_STYLE object.
[0043] The L2S_STYLE is included in the Path, PathTear, PathErr and
Notify messages. The L2S_STYLE immediately follows the
UPSTREAM_FLOWSPEC object in the message encodings.
[0044] The L2S Style is used by the intermediate LSRs to apply
ingress and egress QoS policies in the leaf to source direction of
traffic, i.e., traffic from spoke to hub. When the L2S Style is SE
(Shared Explicit), the egress policer (i.e., egress in the Leaf to
Source direction) is derived from the max value of all the
UPSTREAM_FLOWSPECs of each S2L LSP. When the L2S Style is FF (Fixed
Filter), the egress policer is derived from the sum of the values
of UPSTREAM_FLOWSPECs of each S2L LSP.
[0045] FIG. 3 illustrates a system diagram of a message flow
according to one embodiment. In the P-method, each spoke sends an
UPSTREAM_TSPEC as defined in RFC 6387 in the Resv message. When the
application requires separate flow reservation from each spoke to
the hub, the Fixed Filter (FF) style reservation is used. As
defined in RFC 6387, the format of an UPSTREAM_TSPEC object is the
same as a SENDER_TSPEC object, which includes the definition of
class types and their formats. The intermediate LSRs combine
UPSTREAM_TSPECs received from the upstream LSRs using the Sum Tspec
operation referred to in RFC2205. In this case, the Sum Tspec
operation is a calculation of the sum of all Tspecs supplied by
spokes directly upstream, i.e., from the spoke to hub direction, to
the intermediate LSR. Note that the LSR maintains state within each
Resv State Block (RSB) about the Tspec sent by the upstream LSR.
The hub generates an UPSTREAM_FLOWSPEC to be sent in the Path
message. Using the received UPSTREAM_FLOWSPEC, each intermediate
LSR generates an upstream flow specification to be sent to the
upstream LSR using the following operation called "proportional
flowspec". This operation is described as follows. In one
embodiment, there are n upstream LSRs sending upstream traffic
specifications denoted as UTspec-1, UTspec-2, . . . , UTspec-n. The
intermediate LSR generates an UPSTREAM_FLOWSPEC in proportion to
the Tspec received from the upstream LSRs and directly coupled
spokes. In other words, for an upstream LSR i the Flowspec is
calculated as a fraction (UTspec-i/Sum_Tspec(1, . . . n)) of the
received UPSTREAM_FLOWSPEC.
[0046] FIG. 4 illustrates a system diagram of a message flow
according to one embodiment. In the G-method, each spoke generates
an UPSTREAM_TSPEC as defined in RFC 6387 in the Resv message. The
intermediate LSR does not combine the Tspecs, but rather propagates
the information about the Tspec requested by each spoke, e.g.,
spoke node or leaf node, all the way to the hub. This information
can be conveyed by modifying the packet formats already defined in
RFC 4875 and RFC 6387. There are several ways to modify the packet
format. In one embodiment, instead of the UPSTREAM_TSPEC defined in
RFC6387, a new modified object UPSTREAM_TSPEC_list is used and is
defined as follows. Its encoding is:
TABLE-US-00001 UPSTREAM_TSPEC_list::==UPSTREAM_TSPEC
UPSTREAM_SENDER_TEMPLATE [ UPSTREAM_TSPEC_list ]
[0047] The UPSTREAM_SENDER_TEMPLATE is similar to the
SENDER_TEMPLATE that is defined in RFC 3209. However, in this case,
the IP address in the UPSTREAM_SENDER_TEMPLATE is the address of
the respective spoke. When the hub processes the
UPSTREAM_TSPEC_list, the hub generates an appropriate
UPSTREAM_FLOWSPEC for that S2L sub-LSP, e.g., the path from the hub
to a respective spoke node or leaf node, and signals the S2L
sub-LSP, e.g., using one or more Path messages. As described in RFC
4875, one or more path messages can be used to signal one or more
S2L sub-LSPs. To signal an UPSTREAM_FLOWSPEC per S2L sub LSP, there
are several ways to encode the information. In one embodiment, the
format of the S2L_SUB_LSP is modified by appending an
S2L_SUB_LSP_FLOWSPEC object to it. The format of the
S2L_SUB_LSP_FLOWSPEC is the same as the FLOWSPEC object defined in
RFC 2205. An intermediate LSR processes the object as it would
process a normal FLOWSPEC object except that it now takes into
account the resource sharing mode (i.e. fixed filter (FF), shared
explicit (SE), etc.) and allocates resources accordingly. Note that
in one embodiment, mixed mode allocations are not allowed unless
multiple classes of receivers are contemplated. A main advantage of
this method is that the hub can apply spoke-specific policies for
that HSMP LSP by allocating resources depending on the identity of
a specific spoke, instead of each spoke getting a proportion of the
bandwidth as described in the P-method. This method, however, is
more complex to implement.
[0048] FIG. 5 illustrates a diagram of a method for enabling
efficient resource allocation for point to multi-point signaling
using an intermediate label switch router (LSR) according to one
embodiment. At block 505, upstream traffic specification
information associated with a plurality of spoke nodes is received.
An UPSTREAM_TSPEC, as defined in RFC 6387 in the Resv message, is
received from each spoke, e.g., either directly or through an
upstream LSR.
[0049] At block 510, the upstream traffic specification information
is sent to a hub. In one embodiment, using the P-method, the
intermediate LSRs combine UPSTREAM_TSPECs received from the
upstream LSRs using the Sum Tspec operation referred to in RFC2205.
In this case, the Sum Tspec operation is a calculation of the sum
of all Tspecs supplied by spokes directly or indirectly coupled to
the intermediate LSR. Note that the LSR maintains state within each
Resv State Block (RSB) about the Tspec sent by the upstream
LSR.
[0050] In one embodiment, using the G-method, the intermediate LSR
does not combine the Tspecs, but rather propagates the information
about the Tspec requested by each spoke, e.g., spoke node or leaf
node, all the way to the hub. This information can be conveyed by
modifying the packet formats already defined in RFC 4875 and RFC
6387. There are several ways to modify the packet format. In one
embodiment, instead of the UPSTREAM_TSPEC defined in RFC6387, a new
modified object UPSTREAM_TSPEC_list is used and is defined as
follows. Its encoding is:
TABLE-US-00002 UPSTREAM_TSPEC_list::==UPSTREAM_TSPEC
UPSTREAM_SENDER_TEMPLATE [ UPSTREAM_TSPEC_list ]
[0051] The UPSTREAM_SENDER_TEMPLATE is similar to the
SENDER_TEMPLATE that is defined in RFC 3209. However, in this case,
the IP address in the UPSTREAM_SENDER_TEMPLATE is the address of
the respective spoke.
[0052] At block 515, upstream flow specification information is
received from the hub. When the P-method is used, an upstream flow
specification is received, e.g., in a path message from the hub.
When the G-method is used, the intermediate LSR receives a flow
specification, e.g., a S2L_SUB_LSP_FLOWSPEC object.
[0053] At block 520, the upstream flow specification information is
used to allocate resources among the plurality of spoke nodes
either proportionally or in accordance with a resource sharing
mode.
[0054] When the P-method is used, each intermediate LSR generates
an upstream flow specification to be sent to the upstream LSR or
directly coupled spoke using the "proportional flowspec" operation.
In one embodiment, the intermediate LSR generates an
UPSTREAM_FLOWSPEC in proportion to the Tspec received from the
upstream LSRs and directly coupled spokes.
[0055] When the G-method is used, an intermediate LSR processes the
object as it would process a normal FLOWSPEC object except that it
now takes into account the resource sharing mode (i.e. fixed filter
(FF), shared explicit (SE)) and allocates resources
accordingly.
[0056] FIG. 6 illustrates a block diagram of a method for enabling
efficient resource allocation for point to multi-point signaling
using a hub according to one embodiment. At block 605, upstream
traffic specification information is received.
[0057] In one embodiment, the upstream traffic specification
information is received using the P-method. In the P-method, a
combination of the upstream traffic specifications
(UPSTREAM_TSPECS) of the respective spokes is received by the hub
from the intermediate LSR. The UPSTREAM_TSPECs are combined by the
intermediate LSR using the Sum Tspec operation referred to in
RFC2205. In this case, the Sum Tspec operation is a calculation of
the sum of all Tspecs supplied by spokes directly or indirectly
coupled to the intermediate LSR.
[0058] In one embodiment, using the G-method, the upstream traffic
specification information is an upstream traffic specification
list. The information about the Tspec requested by each spoke,
e.g., spoke node or leaf node, is propagated all the way to the
hub.
[0059] At block 610, the upstream traffic specification information
is used to generate an upstream flow specification information that
allows for the allocation of resources among a plurality of spoke
nodes. This allocation of resources can be made proportionally or
in accordance with a resource sharing mode.
[0060] In one embodiment, the P-method is used. In this embodiment,
the upstream traffic specification information is used to generate
upstream flow specification information (UPSTREAM_FLOWSPEC). The
hub generates an UPSTREAM_FLOWSPEC to be sent in a Path
message.
[0061] In one embodiment, the G-method is used. When the hub
processes the UPSTREAM_TSPEC_list, the hub generates an appropriate
UPSTREAM_FLOWSPEC for that S2L sub-LSP, e.g., the path from the hub
to a respective spoke node or leaf node, and signals the S2L
sub-LSP, e.g., using one or more Path messages. As described in RFC
4875, one or more path messages can be used to signal one or more
S2L sub-LSPs. To signal an UPSTREAM_FLOWSPEC per S2L sub LSP, there
are several ways to encode the information. In one embodiment, the
format of the S2L_SUB_LSP is modified by appending an
S2L_SUB_LSP_FLOWSPEC object to it. The format of the
S2L_SUB_LSP_FLOWSPEC is the same as the FLOWSPEC object defined in
RFC 2205.
[0062] FIG. 7 illustrates an example network node or element, e.g.,
a spoke, an intermediate node, an upstream node, and/or a hub.
Network node 700 comprises a processor (CPU) 705, a memory 710,
e.g., random access memory (RAM) and/or read only memory (ROM), and
various input/output devices 715, (e.g., storage devices, including
but not limited to, a tape drive, a floppy drive, a hard disk drive
or a compact disk drive, a receiver, a transmitter). Network node
700 is capable of enabling efficient resource allocation for point
to multi-point signaling.
[0063] The processes described above, including but not limited to
those presented in connection with FIGS. 1-7, may be implemented in
general, multi-purpose or single purpose processors. Such a
processor, e.g., processor 705, will execute instructions, either
at the assembly, compiled or machine-level, to perform that
process. Those instructions can be written by one of ordinary skill
in the art following the description of presented above and stored
or transmitted on a computer readable medium, e.g., a
non-transitory computer-readable medium. The instructions may also
be created using source code or any other known computer-aided
design tool. A computer readable medium may be any medium capable
of carrying those instructions and include a CD-ROM, DVD, magnetic
or other optical disc, tape, silicon memory (e.g., removable,
non-removable, volatile or non-volatile), packetized or
non-packetized wireline or wireless transmission signals.
[0064] While the invention has been described in terms of several
embodiments, those skilled in the art will recognize that the
invention is not limited to the embodiments described. The
description is thus to be regarded as illustrative instead of
limiting.
* * * * *